1. Field of the Invention
The present invention relates to a system for controlling the start of a vehicle having a running electric motor, such as a hybrid car having an electric motor (as will be shortly called the "motor") and an internal combustion engine or an electric car. More particularly, the present invention relates to a start control system for a vehicle having an automatic transmission capable of changing a non-running range and a running range.
2. Related Art
The internal combustion engine using a fossil fuel such as gasoline is troubled by the exhaust gases or noises, and the fossil fuel itself has a fear of future exhaustion. In recent years, therefore, there has been developed a vehicle which uses electricity as its drive energy. One example is an electric car of the type in which a battery is mounted to drive the motor with its electric energy. Another is a hybrid car which has the internal combustion engine (as will be shortly called the "engine") and the electric motor (or motor).
The former electric car is restricted in the running performance and the carrying capacity due to the battery having a large size and a heavy weight. Another item to be improved is that the range of the driving length to be covered by one charge is limited. In the latter hybrid car, on the other hand, the engine per se can be used not only for the drive but also for generating an electric power to charge the battery while the car is running. These advantages makes this car sufficiently practical under the running circumstances and for the applications.
One hybrid car of this kind is disclosed in JPA6-319210. This hybrid car is constructed such that an automatic transmission connected to an engine is equipped therein with a clutch for selectively connecting a torque converter and a speed change gear mechanism, and such that a motor having a rotor connected to a member integrated with an input shaft is mounted in the automatic transmission.
Generally, the automatic transmission is constructed to set a gear stage by employing a load, as expressed by an accelerator opening, and a vehicle speed as its parameters. At the time of a start from the stopped state, a first speed having the highest gear ratio is automatically set. Thus, if the automatic transmission is set to a running range while the engine is in the stopped state and if the prime mover such as the engine is activated, the car is so driven simultaneously as the automatic transmission is set to the first speed that it starts the run simultaneously with the start of the prime mover.
In order to prevent this situation, there is provided in the prior art a shift lock mechanism for allowing a shift unit of the automatic transmission to make a shift from the non-running range to the running range only if the release condition including the depression of the brake is satisfied.
In the electric car or the hybrid car, however, a controller such as an inverter is brought into a starting state (or standby state) by a starting operation using an ignition key, but the motor is not rotated before the accelerator is operated, so that it is not rotated by the starting operation only. This makes it hardly necessary for the hybrid car, as disclosed in the aforementioned Laid-Open, or the existing general electric car or hybrid car to have a shift lock mechanism, even if it is equipped with the automatic transmission. The Laid-Open itself has failed to disclose the shift lock.
In the case of running with the motor, however, in the so-called "standby state" before the start of the running, only the controller is electrically acting, but no part is performing the mechanical action such as rotation. This makes it impossible to decide whether or not the car is in the standby state on the basis of at least the noises or vibrations. If the starting operation is unavailable even by inserting the key, therefore, it may not be perceived that the vehicle is not in the standby state, before the vehicle is not started even by depressing the accelerator pedal. If, in this case, the key is operated to the starting position, the vehicle may be advanced simultaneously with the key operation, because it is in the accelerator ON state.
In the prior art, on the other hand, there is provided an inhibitor mechanism for preventing the start of the running simultaneously with the start of the driving power source. This inhibitor mechanism is constructed to allow the start of the driving power source while the shift unit of the automatic transmission is set in the non-running range, only if the ignition key is operated from an insertion position (for locking) through an intermediate position (for accessory ON) to a starting position (for starting). Incidentally, the ignition key is further constructed such that it is automatically returned to the intermediate position after operated to the starting position.
In the vehicle employing the motor as its driving power source, however, the controller such as the inverter is brought into the starting state (or standby state) by operating the ignition key to the starting position, but the motor itself is not rotated before the accelerator pedal is depressed. In other words, the motor will not perform any mechanical action such as rotations to cause neither noises nor vibrations when the ignition key is merely operated to the starting position.
When the ignition key is in the intermediate position, it is therefore difficult to discriminate whether the ignition key is returned to the intermediate position after operated to the starting position or not operated to the starting position but is stopped in the intermediate portion.
With the ignition key being in the intermediate position, moreover, it may occur that the vehicle is not run even by changing the shift unit to the running range and by depressing the accelerator pedal, and that it is not found before this state that the motor is not controlled in the standby state.
With the aforementioned inhibitor mechanism being provided in this case, the driving power source is not started even by operating the ignition key to the starting position in the running range. If the aforementioned situation occurs, therefore, the vehicle cannot be started unless the ignition key is operated to the starting position once the shift unit is returned to the non-running range and unless the shift unit is changed again to the running range. As a result, the operations are complicated to raise a problem that the start of the vehicle is delayed.